JP2001181846A - CVD equipment - Google Patents

Abstract

(57) Abstract: The present invention provides a CVD apparatus capable of increasing the use efficiency of a raw material gas and reducing the cost by forming a uniform film at a high speed even on a large component. A vacuum container, a heat insulator disposed in the vacuum container, and a film-deposited film mounted on a surface or inside the heat insulator so that at least a film-forming surface is exposed. A substrate 5 and the heat insulator 4 for heating the film-forming substrate 5
And a heating means disposed around or inside the device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CVD apparatus which is excellent in high speed and uniformity, can increase the use efficiency of a raw material gas, and can reduce the film formation cost. The present invention relates to a CVD apparatus for high-speed film formation.

[0002]

2. Description of the Related Art A CVD (Chemical Vapor Deposition) method is called a chemical vapor deposition method, and is widely used as a process for producing semiconductors or liquid crystals or as a thin film forming method for surface treatment. Various methods have been developed for performing this CVD method. For example, thermal CVD, plasma CVD, microwave plasma CVD, optical CVD, MOCVD (organic metal CVD), and the like.

[0003] Among these various CVD methods, the thermal CVD method has a simpler reaction mechanism than other methods, and is a method suitable for manufacturing large-sized and complicated-shaped products. In particular, this thermal CV
Silicon carbide synthesized by the D method has recently been used as a high-purity material in a semiconductor manufacturing process, and has a thickness of several m.
It is required to produce silicon carbide of m at a lower cost.

However, in the conventional thermal CVD method, generally, the film forming rate is slow, so that a long-time film forming is required, the raw material efficiency is low, and the cost of silicon carbide manufactured by the CVD method is high. Was. In addition, when forming a film on a large-sized substrate, the film thickness tends to be non-uniform.

[0005] Therefore, in order to increase the uniformity of the film thickness and the film forming speed, the internal structure of the CVD furnace has been studied. At this time, since the reaction state of the gas is an important factor for the uniformity of the film thickness, the film formation rate, and the use efficiency of the source gas, it is necessary to improve the gas flow and the diffusion state of the molecules constituting the gas. A furnace structure or a furnace structure considering the temperature distribution of a substrate on which a film is to be formed has been considered.

[0006] For example, a CVD apparatus disclosed in Japanese Patent Application Laid-Open No. 11-67675 has a reaction furnace 40 as shown in FIG.
The substrate 41 on which the film is to be formed is a rotating substrate holder 42.
The heater 4 is mounted on
4 heated. The raw material gas is introduced from the gas supply port 45, passes through the rectifying hole provided in the rectifying plate 46, and is supplied to the film-forming substrate 41 in a rectified manner. And / or react to form a film. The raw material gas and the reaction product gas that have not contributed to the reaction are discharged out of the reaction furnace 40 through the exhaust port 47.

In this apparatus, a uniform gas flow is generated on the surface of the substrate 41 by rectifying the gas flow through the rectifying plate 46 and a gas vortex flow is eliminated. It is described to obtain a quality membrane.

The Japan Institute of Metals, Vol. 41 (1977)
Year) pages 358-367 show that Si ₃
A CVD apparatus capable of obtaining N ₄ has been reported. This CV
As shown in FIG. 5, the D apparatus includes a substrate 52 on which a film is to be formed, which is fixed in a graphite socket 53 in a reaction furnace 51. It is heated to 1100 to 1500 ° C.

In this apparatus, a source gas is introduced from two gas supply ports 55 and 56 and reacts on the substrate 52 to form Si ₃ N _4, while unreacted gas and reaction product gas are exhausted. It is discharged from the mouth 57. This apparatus performs high-speed film formation at a rate of 2 mm / h by directly heating the film-forming substrate 52 by applying current.

[0010]

However, the CVD apparatus shown in FIG. 5 shown in the Journal of the Japan Institute of Metals, Vol. 41 (1977), pp. 358-367, directly heats a substrate on which a film is to be formed. Therefore, there is a problem in that the productivity is low due to energization of individual products, and the structure is inappropriate particularly for large products.

On the other hand, according to Japanese Patent Application Laid-Open No. 11-67675 in FIG. 4, the flow of gas is controlled by using a current plate 46, and the film thickness is made uniform by a furnace structure for preventing generation of gas vortex. Although the crystallinity is enhanced, the film formation rate is low, and film formation on parts other than the substrate on which the film is to be formed is large, and the amount of unreacted gas is large. There was a problem that it would.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a CVD apparatus capable of reducing the cost by increasing the use efficiency of a source gas and forming a film at a high speed even on a large component.

[0013]

SUMMARY OF THE INVENTION The present invention is based on the finding that the cause of low uniformity, film forming rate and raw material use efficiency is that a large amount of film is formed on a member in a furnace other than a substrate on which a film is to be formed. It is based on the above and limits the portion having a sufficient temperature for forming a film in the furnace to only the substrate on which the film is to be formed and the immediate vicinity thereof, thereby suppressing the consumption of the source gas on the furnace wall and the jig. The purpose of the present invention is to improve the material use efficiency and the film forming speed.

[0014] The CVD apparatus of the present invention comprises a vacuum vessel, a heat insulator disposed in the vacuum vessel, and a substrate mounted on the surface or inside of the heat insulator so that at least a film forming surface is exposed. A film substrate, and a heating means disposed around or inside the heat insulator to heat the film-forming substrate, and having this structure, It is possible to improve the use efficiency and to perform high-speed film formation on a large product.

Preferably, the means for heating the substrate to be deposited is high-frequency induction heating, whereby only the substrate to be deposited can be efficiently heated. In particular, it is preferable that the substrate on which the film is to be formed is an insulator, and the heating means for the substrate to be formed is heat generated by high-frequency induction heating of a conductive material arranged so as to be in contact with the substrate. Thus, the insulator can be more efficiently and rapidly heated.

The substrate on which the film is to be formed is preferably in the shape of a disk or a ring, and high frequency can be used effectively for heating. Further, it is desirable that the number of turns of the high-frequency induction coil used for the high-frequency induction heating be one and that the high-frequency induction coil be located at substantially the same height as the substrate on which the film is to be formed. High frequency can be efficiently absorbed by the film substrate, and unnecessary high frequency output used for heating other than the substrate on which the film is to be formed can be omitted.

Alternatively, the means for heating the substrate on which the film is to be formed is:
It is resistance heating by a heater made of metal or carbon, and it is preferable that the heater is buried inside the heat insulator and / or the substrate on which the film is to be formed. Thereby, even if the substrate on which the film is to be formed has a complicated shape, uniform heating is performed, and the uniformity of the film thickness and film quality can be improved. In particular, it is preferable that an insulator be provided between the deposition target substrate and the heater, and at least a portion of the deposition target substrate and at least a portion of the heater be in contact with the insulator. Thereby, the heat of the heater is efficiently transmitted to the substrate on which the film is to be formed, and the time required for increasing the temperature of the substrate on which the film is to be formed is reduced, which can contribute to cost reduction. Further, it is preferable that the heat insulator is made of a porous material. This is because the cold gas permeates into the inside, so that the heat insulator can be efficiently cooled and the temperature rise of the heat insulator can be suppressed. In addition, it is preferable that the heat insulator has a slit or that the fiber direction of the heat insulator is substantially parallel to the surface of the substrate on which the film is to be formed, thereby improving heat insulation and increasing the temperature of the heat insulator. Can be suppressed. Therefore, only the substrate on which the film is to be formed can be effectively heated, and the use efficiency of the raw material can be further improved.

Further, it is preferable to have a means for cooling the heat insulator, whereby the temperature rise of the heat insulator can be further suppressed, and the waste of the film forming material gas can be reduced. Low cost can be expected.

It is preferable that a gas nozzle for supplying a source gas is provided to face the substrate on which the film is to be formed. By employing this structure, the supply of the raw material onto the substrate on which the film is to be formed becomes sufficient, and the film formation speed can be remarkably increased. Further, it is preferable to provide a means for rotating the substrate on which the film is to be formed, in that the uniformity of the film thickness can be improved.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a CVD apparatus of the present invention, the periphery of a substrate on which a film is to be formed is held by a heat insulator, only the substrate on which the film is to be formed is kept at a high temperature, and the consumption of the source gas in other than the substrate on which the film is to be formed is suppressed. A vacuum vessel, a heat insulator disposed in the vacuum vessel, and at least a surface or inside of the heat insulator. A film-forming substrate arranged so that a film surface is exposed, a support jig for fixing the heat insulator and / or the film-forming substrate,
Means for heating the substrate on which the film is to be formed.

For example, as shown in FIG. 1A, a vacuum vessel 1 is composed of a flange 2 and a vacuum wall 3, and a film-forming substrate 5 is buried in a heat insulator 4 provided inside the vacuum vessel 1. And
It is fixed to the heat insulator 4 by a fixing jig 6 so that the film formation surface 5a is exposed. The heat insulator 4 is supported by a support jig 7, and the support jig 7 is fixed to the flange 2.

A gas pipe 8a for supplying a raw material gas and an exhaust port 9 for discharging waste gas are provided on the upper and lower flanges 2. The gas nozzle 8b is arranged at a desired distance from the film formation surface 5a, and is provided with a plurality of gas nozzles 8b branched from the gas pipe 8a. The gas flow is indicated by arrows. The substrate 5 is directly heated by high-frequency induction heating using the high-frequency induction coil 10.

The inside of the vacuum vessel 1 is evacuated by a vacuum pump or the like, and when a predetermined degree of vacuum is reached, hydrogen or an inert gas is introduced, and high-frequency power is applied to the high-frequency induction coil 10 to apply the high-frequency power to the high-frequency induction coil 10. Heat. The film-forming substrate 5 has a CV
When the temperature is maintained at the temperature D or higher, the source gas is introduced into the vacuum chamber 1 from the gas nozzle 8b via the gas pipe 8a, and the source gas is decomposed and / or reacted on the surface of the substrate 5 on which the film is to be formed. The unreacted gas and the reaction product gas generated by the reaction are exhausted from the exhaust port 9.

For example, an inner diameter of 190 mm and an outer diameter of 210 mm
A film-forming substrate 5 made of high-purity carbon is installed so as to be embedded in a heat insulator 4 made of carbon as shown in FIG. 1A, and the inside of the vacuum apparatus 1 is an oil rotary pump and a mechanical booster pump. Alternatively, the pressure is reduced by a general vacuum pump such as a dry pump. Then, for example, when the degree of vacuum becomes 1 Pa or less, hydrogen gas is introduced, the pump is switched to a water ring type pump, and the pressure in the vacuum vessel 1 is maintained at 3 kPa. Here, a water-sealed pump is used because it is easy to treat HCl generated by CVD, but a desired pump can be used depending on the raw materials, processing equipment, and operating pressure.

Next, a high frequency is applied to the high frequency induction coil 10 having one winding, and the substrate 5 is heated by high frequency induction heating. Ten minutes later, when the temperature reached 1500 ° C,
A mixed gas of hydrogen and methyltrichlorosilane is introduced from the gas nozzle 8b to form a film. With this method, a silicon carbide film of 1 mm or more can be obtained in one hour. Further, by removing the substrate 5 mechanically or chemically, a bulk material can be manufactured in a short time and at low cost.

The vacuum vessel 1 is composed of a flange 2 and a vacuum wall 3 in FIG. 1A, and the joint is vacuum-sealed with viton rubber or the like. Flange 2
May be a general metal material such as stainless steel, but it is preferable to use a corrosion-resistant material such as SUS316 because a chlorine-based gas is used. Further, it is preferable to cool the flange 2 by water cooling or the like in order to avoid an increase in the temperature of the vacuum seal portion.

The vacuum wall 3 can be made of a material that hardly absorbs high frequency, for example, ceramics such as quartz glass, silicon nitride, alumina, aluminum nitride, YAG, or spinel. Since a chlorine-based gas is used, it is preferable to use a corrosion-resistant material such as high-purity alumina or YAG.

The heat insulator 4 has an effect of limiting a portion having a sufficient temperature for film formation to the substrate 5 on which the film is to be formed. Covers the periphery of the film-forming substrate 5. In FIG. 1A, the surface on which the substrate 5 is formed in a ring shape is only one surface,
Regardless of the shape, it is preferable to cover the surface other than the film-forming surface with a heat insulator and to form the film only on the film-forming surface in order to increase the raw material efficiency. When the deposition target substrate 5 has a complicated shape, a plurality of heat insulators may be combined to cover the non-deposition surface of the deposition target substrate 5. The substrate 5 to be deposited may be embedded in the heat insulator 4, but may be simply placed on the heat insulator when there are many deposition surfaces.

The heat insulator 4 preferably has a large thermal resistance. For example, a material using graphite or ceramic can be used.
Those containing fibrous materials such as oxide fiber-based heat insulating materials and graphite fibers are preferred. In particular, a heat insulator using graphite fibers is preferable in terms of cost. Also, considering heat insulation,
The thermal conductivity is preferably 0.5 W / mK or less, particularly 0.3 W / mK, and the temperature rise of the heat insulator 4 can be prevented.
Furthermore, considering workability, the bulk density of the heat insulator 4 is
1.0 g / cm ³ or less, particularly preferably 0.7 g / cm ³ or less, and more preferably 0.5 g / cm ³ or less.

Since graphite has conductivity, when a heat insulator using graphite fibers is used, the heat insulator 4 itself may be heated by high frequency depending on the frequency and output. When the temperature of the heat insulator 4 becomes equal to or higher than the film forming temperature, the heat insulator 4
A film is formed on the surface. Therefore, in order to suppress this film formation, it is preferable to prevent a temperature rise of the heat insulator 4 and to suppress the diffusion of heat. That is, it is preferable to provide a plurality of slits on the surface of the heat insulator 4 in a direction perpendicular to the high-frequency induction coil surface so that the current induced by the high frequency does not easily flow on the surface. Note that the number and depth of the slits may be determined in consideration of the operating frequency and the allowable temperature.

Alternatively, the direction of the fibers in the heat insulator 4 is preferably substantially parallel to the surface of the substrate 5 on which the film is to be formed. That is, in FIG. 1B, the right end face of the substrate 5 on which the film is to be formed comes into contact with the heat insulator 4 composed of the laminate of the two-dimensional fabric 4a, and heat is easily transmitted in the in-plane direction of the two-dimensional fabric 4a.
Conversely, since heat is not easily transmitted between the two-dimensional fabrics 4a, the surface of the substrate 5 on which the film is to be formed and the two-dimensional fabric 4a may be substantially parallel as shown in FIG. For example, the in-plane thermal conductivity of the two-dimensional fabric 4a may be 0.7 W / mK, and 0.3 W / mK in the direction between the two-dimensional fabrics 4a perpendicular to the plane direction.

Since the heat insulator 4 is in contact with the substrate 5 on which the film is to be formed, the vicinity of the heat insulator 4 is heated, and the temperature of the heat insulator 4 as a whole may increase with time. In such a case, in order to lower the surface temperature of the heat insulator 4, the heat insulator 4
It is preferable to provide a cooling mechanism such as flowing an inert gas to the surface and / or inside. Thereby, film formation on the surface of the heat insulator 4 can be prevented.

The substrate 5 on which the film is to be formed is fixed to the heat insulator 4 by a fixing jig 6. The fixing jig 6 is made of a material such as carbon or high melting point metal such as Mo, and can be processed into a bolt shape and used. When the fixing jig 6 is a conductor, the fixing jig 6 is heated. Therefore, it is desirable that the fixing jig 6 be installed so as to be housed in a heat insulator.

The supporting jig 7 can stably support the weight of the heat insulator 4, the substrate 5 and the fixing jig 6, and the heat insulator 4 and the substrate 5 can be used during operation of the apparatus. In this case, a heat insulating material or an insulator can be used. For example, if the heat insulator 4, the substrate 5 and the fixing jig 6 are light, a heat insulator can be used. If the heat insulator 4 is heavy, a ceramic such as alumina, silicon nitride or quartz glass can be used.

The method of introducing the source gas into the vacuum vessel 1 is not particularly limited, and the source gas may be supplied to the surface of the substrate 5 on which the film is to be formed. In order to increase the temperature, it is preferable to set the temperature of the substrate on which the film is to be formed at a high temperature, and to provide the tip of the gas nozzle 8b at a specific distance from the surface of the substrate on which the film is to be formed, as shown in FIG. If the temperature rise of the gas nozzle 8b due to heat radiation from the substrate on which the film is formed and heat conduction using a gas as a medium is remarkable, it is preferable to provide a cooling mechanism for the gas nozzle 8b.

The gas nozzle 8b may be made of either the same material as the gas pipe 8a or a different material. Generally, SUS or the like which has high corrosion resistance and is easy to process can be used. However, when the high frequency is absorbed and the temperature of the gas nozzle 8b rises, it is preferable to use an insulator such as alumina or silicon nitride for the gas nozzle 8b. When such a ceramic is used as a gas nozzle, it may be connected to the gas pipe 8a in a tube shape, or a raw material gas may be sprayed on the film forming surface 5a using a porous material like a gas shower.

A general vacuum pump can be used for exhausting the gas. For example, an oil rotary pump, a mechanical booster pump, a dry pump, a turbo molecular pump, a water ring type pump, or the like can be used according to the degree of vacuum.
Among these, when a film is formed under reduced pressure and a large amount of halide is used as a raw material, it is preferable to provide a pump for initial evacuation and a pump for CVD separately.

In the high frequency induction heating, an electric current is applied to the surface of the substrate on which the film is to be formed, so that the substrate is directly heated, so that the energy efficiency is high. can do.
Further, it is preferable that the substrate on which the film is to be formed has a ring shape because the high frequency can be efficiently absorbed.

In the high-frequency induction heating, since the surface current penetration depth varies depending on the frequency, it is necessary to select a frequency in accordance with the shape of the substrate to be efficiently heated in order to heat the substrate. Therefore, although the substrate 5 is not particularly specified, it is necessary to generate a current on the surface of the substrate 5 in high-frequency induction heating by high frequency. The material must be a material, and a high melting point metal such as carbon or Mo is preferable.

The height of the high-frequency induction coil is a factor that affects high-frequency energy per unit height. For example, when heating a thin film-formed substrate such as a ring, the coil is also formed in a thin ring shape and the number of windings is set to one so that high-frequency energy can be concentrated on the film-formed substrate. The film formation substrate can be efficiently heated. With these designs, it is possible to heat to the CVD temperature in a short time of 5 to 30 minutes, depending on the shape and material of the substrate 5 for film formation.

The members that come into contact with the film-forming raw material gas in the vacuum apparatus, such as the fixing jig and the supporting jig used in the CVD apparatus of the present invention, can be selected from desired materials. For example, when manufacturing a high-purity CVD film, it is required to suppress the mixing of metal impurities, so that members such as a fixing jig and a supporting jig are made of a high-purity material such as high-purity graphite or quartz glass. Use is required. In addition, it is preferable to use a special alloy such as SUS, Hastelloy, and Inconel for a member in which use of a metal material such as a pipe is indispensable.

With the CVD apparatus of the present invention, a CV capable of high-efficiency raw materials, high-speed, and capable of performing CVD even on large parts
A D device can be provided. That is, metal carbides, nitrides, carbonitrides, oxides, borides, silicides, halides, metals, alloys, and the like can be formed at a high speed on a large-sized substrate, and product cost can be kept low. it can. For example, when used for forming a silicon carbide film, 1
Since a high-purity silicon carbide film having a thickness of 3 to 10 mm can be easily obtained in 3 hours, the obtained film can be separated from a substrate on which a film is to be formed, and a ceramic or metal bulk material can be obtained. is there.

By the way, the method of heating the substrate on which the film is formed may be any method as long as the substrate on which the film is formed reaches a predetermined temperature. For example, the means for heating the film-forming substrate 5 in FIG. 1A is high-frequency induction heating and is limited to the case where the film-forming substrate 5 is a conductor. For example, when the substrate is silicon carbide and an insulator, A heating element made of a conductor is disposed directly under the substrate 5 to be covered with the heat insulator 4, and the heating element is heated by high-frequency induction heating, so that the substrate 5 can be indirectly heated. . Further, a heater by resistance heating may be provided near the substrate in the vacuum vessel 1, or heating may be performed by applying a current directly to the substrate 5 on which the film is to be formed. For example, the film-forming base 5 is disposed so as to be embedded in the heat insulator 4,
In addition, a heater for resistance heating is provided inside the heat insulator 4, the heater is heated by energization, and the substrate 5 can be heated by the heat. An example is shown in FIG.

FIG. 2 shows another CVD apparatus of the present invention.
The vacuum vessel 11 is composed of a flange 12 and a vacuum wall 13, and a film-forming substrate 15 is buried in a heat insulator 14 provided inside the vacuum vessel 11, and is arranged so that a film-forming surface 15a is exposed. The heat insulator 14 is supported by a support jig 17, and the support jig 17 is fixed to the flange 12.

A gas pipe 18a for supplying a raw material gas
And an exhaust port 19 for discharging waste gas are provided between the upper and lower flanges 12.
It is provided in. The gas nozzle 18b is arranged at a desired distance from the film forming surface 15a, and is made of porous ceramics. The heating of the film-forming substrate 15 is performed by:
Heated by a heater 20 provided inside the heat insulator 14. Then, the deposition target substrate 15, the heater 20, and the heat insulator 1
4 and the support jig 17 can rotate integrally. The rotation speed can be set, for example, to 10 to 500 rpm.

The raw material gas enters the cavity 18c via the gas pipe 18a, is blown out in a shower form from a gas nozzle 18b made of porous ceramics, and is supplied to the film forming surface 15a of the substrate 15 on which the film is formed. It is formed. The porous ceramics can supply a uniform gas flow over a relatively large area by, for example, a silicon carbide sintered body having a porosity of 8 to 40%.

FIG. 3 shows still another CVD apparatus of the present invention. The vacuum vessel 21 is composed of a flange 22 and a vacuum wall 23, and a film-forming substrate 25 is embedded in a heat insulator 24 provided inside the vacuum vessel 21, and is arranged so that a film-forming surface 25 a is exposed. The substrate 25 has a dome shape, and a film is formed on the outer surface. Also, the heat insulator 24
Is supported by a support jig 27, and the support jig 27 is fixed to the flange 22. However, the film formation substrate 25
Is simply placed in the depression on the heat insulator 24, and the substrate 25, the heat insulator 2
4 and the support jig 27 are fixed.

Further, a gas pipe 28a for supplying a raw material gas and an exhaust port 29 for discharging waste gas are provided on the upper and lower flanges 22. The gas nozzle 28b is
It is arranged at a desired distance from the film forming surface 25a and is made of porous ceramics. The substrate 25 is heated by a heater 30 provided inside the heat insulator 24. The substrate 25, the heater 30, the heat insulator 24, and the support jig 27 can be integrally rotated. The rotation speed can be set, for example, to 10 to 500 rpm.

The substrate 25 to be formed is heated by the heater 30 via the insulator 31. Therefore, for effective use of heat, the insulator 31 is preferably a material having high thermal conductivity. That is, the thermal conductivity of the insulator 31 is preferably 50 W / mK, more preferably 80 W / mK.
mK, more preferably 100 W / mK.
For example, Si ₃ N ₄ , AlN, SiC, or the like can be used.

The raw material gas is blown out from the gas nozzle 28b via the gas pipe 28a and supplied to the film-forming surface 25a of the substrate 25 to form a film. The porous ceramics can supply a uniform gas flow over a relatively large area by, for example, a silicon carbide sintered body having a porosity of 8 to 40%.

According to the present invention, even if the substrate to be formed has a complicated shape such as a dome shape, the efficiency of the raw material is high, the CVD is performed at a high speed, and the CVD can be performed even on a large part.
An apparatus can be provided.

[0052]

Example 1 A silicon carbide film was formed on a ring-shaped carbon film-forming substrate using the CVD apparatus of the present invention shown in FIG.

The CVD apparatus of the present invention is the apparatus shown in FIG. 1A, wherein the flange 2 is made of SUS316 and is water-cooled, and the vacuum wall 3 is made of quartz glass. The substrate 5 has an outer diameter of 210 mm, an inner diameter of 190 mm, and a thickness of 1 mm.
High-purity graphite of 0 mm, outer diameter 260 mm, inner diameter 15
It is embedded in a graphite felt molded heat insulator 4 having a thickness of 0 mm and a thickness of 35 mm, and is fixed by a carbon fixing jig 6.

Further, as shown in FIG.
The two-dimensional fabric 4a is arranged such that the direction of the two-dimensional fabric 4a, that is, the fiber direction is substantially parallel to the film-forming surface 5a of the substrate 5 on which the film is to be formed. Is supported by a support jig 7 made of quartz, and the gas nozzle 8b is made of quartz glass.
Six are arranged. The gas nozzle 8 b was set at a position 20 mm immediately below the substrate 5 on which the film was formed.

The inside of the vacuum vessel 1 was evacuated with a rotary empty pump until the degree of vacuum reached 1 Pa or less. Hydrogen gas was introduced at a flow rate of 5 l / min. The pump was switched to a water ring pump, the pressure was maintained at 1 kPa,
To which high frequency power was applied. High frequency is 20kHz
Then, the output was adjusted using a radiation thermometer so that the temperature of the film-forming substrate 5 became 1500 ° C. Start heating for 5 minutes 1
500 ° C. was reached.

The temperature of the substrate 5 is maintained at 1500 ° C., and a mixed gas of methyltrichlorosilane gas and hydrogen gas is used as a raw material gas at 1.5 l / min and 10 l / min.
The flow was performed at a flow rate of min, and the pressure in the vacuum vessel 1 was adjusted to be approximately 2.7 kPa. After 3 hours, introduction of the methyltrichlorosilane gas was stopped, and then heating was stopped.

After the completion of the CVD, the weight of the substrate was measured, and the weight increase was defined as the amount of the CVD SiC, and the raw material efficiency was calculated with the case where methyltrichlorosilane was completely converted to SiC as 100. In addition, the silicon carbide film was broken into approximately eight equal parts together with the ring-shaped substrate to be formed, each cross section was photographed with a microscope, and the thickness of the film formed on the film formation surface was measured. Calculated.

As a result, the raw material efficiency was 25% and the film thickness was 3.
5 mm. Comparative Example A silicon carbide film was formed using the conventional CVD apparatus shown in FIG. The reactor 20 is made of SUS304, and its outer wall is water-cooled. The substrate 4 on which the film is to be formed, which is placed on the substrate holder 42.
1 was rotated at 30 rpm and heated to 1500 ° C. Further, a carbon cylinder is provided outside the substrate holder 42 to protect the rotation shaft 43.

As a raw material gas, a mixed gas of methyltrichlorosilane and hydrogen gas was 1.5 l / min.
It was passed through at a flow rate of 0 l / min. The pressure in the vacuum vessel 40 was adjusted to be approximately 2.7 kPa, and the film was formed for 3 hours.

The raw material efficiency and the film thickness of the obtained silicon carbide were measured in the same manner as in Example 1.

As a result, the raw material efficiency was 5% and the film thickness was 0.5
mm. Example 2 Film formation was performed using the same apparatus as in Example 1 except that the number of turns of the high-frequency induction coil, the type of heat insulator, and the presence or absence of the gas nozzle were changed.

The raw material efficiency and the film thickness of the obtained silicon carbide film were measured in the same manner as in Example 1. The temperature of the film-forming substrate during the CVD reaction was measured by a radiation thermometer, and the surface temperature of the heat insulator was measured by an infrared radiation thermometer.
The high frequency output when reaching 500 ° C. was recorded. Table 1 shows the results.

In Table 1, "1 turn" in the number of turns of the coil means a high-frequency induction coil in which a 20 mm square copper pipe is wound, and "5 turns" means a high-frequency induction coil in which the same copper pipe is wound 5 times. It uses induction coils.

In the slits of the heat insulator, “No” means that the slit processing is not performed, and “Yes” means that the slit processing is performed at 8 places at equal intervals with a slit processing of 15 mm in depth and 1 mm in width from the outer periphery. Means the use of

Further, "parallel" on the surface of the heat insulator means that the surface of the heat insulator is covered by a surface parallel to the graphite fiber direction, and "vertical" means a surface perpendicular to the graphite fiber direction. Means to be covered by

Furthermore, in the cooling of the heat insulator, "Yes"
The term means that argon gas is blown to the outer side wall of the heat insulator.

In the gas nozzle, "none" means that the gas nozzle was not provided and the raw material gas was supplied from the furnace wall of the reactor.

[0068]

[Table 1]

Sample No. of the present invention In Nos. 1 to 7, the raw material efficiency was 22% or more and the average film thickness was 3 mm or more. In particular, the sample No. was prepared by slitting the heat insulator and covering the surface of the heat insulator with a surface parallel to the fiber direction of the heat insulator. 3 is
At a low power of 17 kW, the raw material efficiency reached 27%. Example 3 A silicon carbide film was formed on a disk-shaped carbon deposition substrate using the CVD apparatus of the present invention shown in FIG.

The flange 12 and the vacuum wall 13 of the vacuum vessel 11 are made of SUS304 and are integrated, and the whole is water-cooled. The film formation substrate 15 has a diameter of 180 m.
m, high-purity graphite having a thickness of 5 mm, and a carbon heater 20 directly below a silicon nitride plate having a thickness of 2 mm.

The heat insulator 14 formed so that its fiber direction is substantially parallel to the surface of the substrate on which the film is formed is supported by a support jig 17 made of alumina.
“b” is made of porous silicon carbide having a diameter of 150 mm and is set at a position of 40 mm immediately above the substrate 5 on which the film is to be formed.

The operation of the apparatus was performed in the same manner as in Example 1.
A silicon carbide film was obtained.

The raw material efficiency reached 22%. Example 4 A silicon carbide film was formed on a dome-shaped carbon deposition substrate using the CVD apparatus of the present invention shown in FIG.

The flange 22 and the vacuum wall 23 of the vacuum vessel 21 are made of SUS304 and are integrated, and the whole is water-cooled. The substrate 25 to be formed has a diameter of 300 m.
m, high-purity graphite having a thickness of 5 mm and a height of 100 mm, and an insulator 31 made of aluminum nitride having a thickness of 2 mm
A carbon heater 30 is provided directly below the heater.

The heat insulator 24 formed so that its fiber direction is substantially parallel to the surface of the substrate on which the film is formed is supported by a support jig 27 made of alumina.
Is made of porous silicon carbide having a diameter of 150 mm.
5 was set at a position of 40 mm immediately above.

The gas nozzle 28b was shaped as shown in FIG. Then, the operation of the apparatus was performed in the same manner as in Example 1 except that a voltage was applied to the heater instead of applying the high-frequency power to the high-frequency induction coil, to obtain a silicon carbide film.

The raw material efficiency reached 20%. Example 5 Various films were formed on a ring-shaped carbon film-forming substrate using the CVD apparatus of the present invention shown in FIG.

The shape, apparatus and operation of the substrate 5 were the same as in Example 1. The results are shown in Table 2.

[0079]

[Table 2]

In each case, a high raw material efficiency of 15% or more was obtained.

[0081]

According to the CVD apparatus of the present invention, a substrate to be deposited is buried in a heat insulator, and a portion at which the temperature rises is limited by arranging the substrate to be exposed so that the deposition surface is exposed. The use efficiency of the source gas is improved, high-speed film formation can be performed on a large substrate, and product cost can be reduced.

[Brief description of the drawings]

FIG. 1 shows a CVD apparatus of the present invention.
FIG. 3B is a cross-sectional view of the VD apparatus, and FIG.

FIG. 2 is a sectional view showing another CVD apparatus of the present invention.

FIG. 3 is a sectional view showing still another conventional CVD apparatus.

FIG. 4 is a sectional view showing a conventional CVD apparatus.

FIG. 5 is a sectional view showing another conventional CVD apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Vacuum container 2 ... Flange 3 ... Vacuum wall 4 ... Heat insulator 4a ... Two-dimensional fabric 5 ... Film-forming base 6 ... Fixing jig 7 ... Support Jig 8a ・ ・ ・ Gas pipe 8b ・ ・ ・ Gas nozzle 9 ・ ・ ・ Exhaust port 10 ・ ・ ・ High frequency induction coil

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4K030 AA03 AA06 AA17 BA27 BA29 BA48 CA12 EA04 FA10 GA02 GA08 KA05 KA09 KA23 5F045 AB06 AC05 AD18 AF07 AF11 BB08 BB09 DP27 EB03 EC05 EF05 EJ01 EK02 EK07

Claims (13)

[Claims] A vacuum container, a heat insulator disposed in the vacuum container, a film-forming substrate mounted on a surface or inside of the heat insulator so that at least a film-forming surface is exposed; A heating means disposed around or inside the heat insulator for heating the substrate on which the film is to be formed.
D device. 2. The CVD apparatus according to claim 1, wherein the means for heating the substrate on which the film is formed is high-frequency induction heating. 3. The method according to claim 1, wherein the substrate on which the film is to be formed is an insulator, and the means for heating the substrate for forming the film is generated by high-frequency induction heating of a conductive material disposed in contact with the substrate. The CVD apparatus according to claim 2, wherein: 4. The CVD apparatus according to claim 2, wherein the substrate on which the film is to be formed has a disk or ring shape. 5. The high-frequency induction coil used for high-frequency induction heating has one winding, and the high-frequency induction coil is at substantially the same height as the substrate on which the film is to be formed. A CVD apparatus according to any one of the above. 6. A heater for heating a substrate on which a film is to be formed is a heater made of metal or carbon.
2. The CVD apparatus according to claim 1, wherein the CVD apparatus is buried inside the substrate on which the film is to be formed. 7. An insulator is provided between a deposition target substrate and a heater, and at least a part of the deposition target substrate and at least a portion of the heater are in contact with the insulator. The CVD apparatus according to claim 6. 8. The CVD apparatus according to claim 1, wherein the heat insulator is made of a porous material. 9. The CVD apparatus according to claim 8, wherein the heat insulator has a slit. 10. The CVD apparatus according to claim 9, wherein the heat insulator contains a fibrous body, and the fiber direction of the fibrous body is substantially parallel to the surface of the substrate on which the film is to be formed. 11. The CV according to claim 1, further comprising means for cooling the heat insulator.
D device. 12. The CVD apparatus according to claim 1, wherein a gas nozzle for supplying a source gas is provided to face the substrate on which the film is to be formed. 13. The CVD apparatus according to claim 1, further comprising means for rotating the substrate on which the film is to be formed.